Rosacea May Be Triggered by Skin Bugs

About 16 million Americans suffer from a skin condition known as rosacea. Although some triggers have been identified, the underlying cause has been a mystery. Researchers in Ireland, however, are a step closer to establishing a bacterial cause for the condition.

Rosacea is a chronic skin condition that tends to affect fair-skinned females, causing redness, swelling and skin sores that look like acne. Doctors know that it involves the blood vessels just under the skin that swell, causing a spider-like appearance on the face known as telangiectasia. Although it is a harmless condition, it may cause self-consciousness and embarrassment especially in more severe cases where it can be painful and disfiguring.

Researchers from the National University of Ireland have discovered that rosacea may be triggered by bacteria that live within tiny mites that reside in the skin. The species is known as Demodex folliculorum and is worm-like in shape. It is a normal inhabitant of the face, living inside the pilosebaceous structure that surrounds the hair follicles, but its number increases with age and skin damage. People with rosacea have higher levels of the mite than those with normal skin.

The bacterium Bacillus oleronius has been isolated in the digestive tract of the Demodex mite. When the mites die, the bacteria are released into the skin. This appears to provoke an immune reaction in rosacea patients and trigger inflammation and tissue degradation.

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Fortunately, the bacterium is sensitive to the antibiotics already used to treat rosacea. But unfortunately, the antibiotics have no effect on the mite itself, which may explain why the antibiotics only work temporarily. Rosacea patients continue to pick up Bacillus-infected mites from other people, such as relatives and friends, and the cycle continues.

“Targeting these bacteria may be a useful way of treating and preventing this condition," said Dr. Kevin Kavanagh who conducted the research for the University. "Alternatively we could look at controlling the population of Demodex mites in the face. Some pharmaceutical companies are already developing therapies to do this, which represents a novel way of preventing and reversing rosacea."